RSpec/ExampleGroupArgument cop draft

a_spec.rb

RSpec.describe do
  # good
  describe MyClass do
  end
  describe 'sdfsd' do
  end
  describe "sfa #{dfsdf}" do
  end

  # questionable
  describe VERSION do
  end

  # acceptable
  describe variable do
  end
  # no real issue, just incorrect usage of the first argument
  describe [1,2,3] do
  end
  describe a: 1 do
  end
  describe :sdfsf do
  end

  # bad
  describe [1,2,3] do
    described_class
  end
  describe a: 1 do
    described_class
  end
  describe :sdfsf do
    described_class
  end
end

example_group_argument.rb

# frozen_string_literal: true

module RuboCop
  module Cop
    module RSpec
      class ExampleGroupArgument < Cop
        MSG             = 'Bad first argument for example group'

        def_node_matcher :example_group?,
                         RuboCop::RSpec::Language::ExampleGroups::ALL.block_pattern

        def_node_search :dangerous_method_call?, <<-PATTERN
          (send nil? { :it_behaves_like :inlcude_examples :described_class })
        PATTERN

        def on_block(node)
          return unless example_group?(node)
          return unless node.send_node.arguments? # though not having any arguments is bad, too

          first_argument = node.send_node.arguments.first
          return unless offensive_first_argument?(first_argument)

          add_offense(node) if dangerous_method_call?(node)
        end

        def offensive_first_argument?(node)
          # local variables are also bad, as they are an indication of
          # https://rspec.rubystyle.guide/#it-in-iterators
          !(node.str_type? || node.dstr_type? || node.const_type? || node.lvar_type? || node.send_type?)
        end
      end
    end
  end
end